Fraggle As a good scientist, you will appreciate the value of hard data. I challenge you to do the calculation. The facts are : Ocean size E18 tonnes of seawater. Radio-isotopes currently produced as part of nuclear waste - less than 200 tonnes per annum. Current radioactive element content of the oceans - more than 50 million tonnes. Queries : 1. How concentrated will radio-isotope levels in the ocean be after 1000 years of dumping all nuclear waste in the oceans, assuming good mixing? 2. How does this compare to the 'natural' background level of radioactive material currently dissolved in the oceans? 3. After doing the sums, do you still feel the same about this method of disposing of waste?
LG Which of my numbers do you think is speculation? The oceans genuinely contain 1,000,000,000,000,000,000 tonnes of water. Radio-isotope production as nuclear waste is geninely less than 200 tonnes per year. The oceans genuinely contain more than 50 million tonnes of radioactive elements. The calculations are simple, really. If we use 200 tonnes per year, then each year the amount of radioactive material entering the oceans amounts to 5 parts in 1000 trillion. In 1000 years, that become 5 parts per trillion. Current 'natural' levels are 20 parts per billion, or 10 times the maximum level of 'artificial' radio-isotopes that would be achieved by dumping all our nuclear waste in the oceans for 1000 years. If we could maintain that level of nuclear power. If we had not moved to fusion power. Many 'ifs'. Question 3 still remains unanswered.
How about we check out the key assumptions, very carefully, before we st up our entire energy economy to be based on the dumping of tons of filthy and lethal waste somewhere we can't get it back? Especially since the whole project is the most expensive form of energy generation known this side of one-shot hand made satellite solar panels? And if we don't need it, and really wish it ahd never been made, it will be easy to access. Quite possibly by turning on the faucet in the kitchen. OK - that vetoes that idea. But the economics already killed it among the sane. Why not go for cheap? Thermal solar, say, with DC transmission lines.
Nuclear power economics are not too bad. The following are 2005 American figures, so it may have changed a little. Results are American cents per kilowatt hour cost of electricity production. Hydro-electricity 5.8 cents Coal burning power 6 cents Nuclear 7.5 cents Wind power 10 cents Solar cell 25 cents. Most of the cost of nuclear power is the initial commissioning cost, plus the final decommissioning cost. Fuel elements are only 5 to 10% of the cost of nuclear power. Both hydro and coal are cheaper, but in most places hydro has already peaked out, and coal has nasty climate change consequences. Incidentally, I also read an estimate of the cost of coal generated power if the CO2 generated is stored deep underground - 10 cents - equal to wind power. In relation to disposing of nuclear waste - I described my personal preference before - using discarded open cast mines in deserts, in geologically stable areas such as is available in Australia and southern Africa. The 'dissolve in sea water' system is my second choice, but has the advantage that it is final.
Yep. That whole area might end up underwater. In which case we'd have a radioactive area in a lake instead of on a dry plateau. Ironically, NOT having a place to store waste might just hasten that day. Not at all. Civilization may collapse, in which case we won't need what's in those storage casks, and they may become relics of the past. Heck, people may even worship them, and wonder why the snow melts on them faster than it does other places. Or civilization may rise again, and people may learn why we once stored nuclear waste that way. Of course, by that time, they may no longer be all that useful (or all that radioactive) any more.
If you don't like the idea of it sticking around, dump the solid waste into a subduction zone. In ten thousand years it will be on its way back to the mantle of the planet. Not really; see the post above mine. Yes, that is unlikely but possible. Yet right now we trade that possibility for the certainty that we are breathing in the tons of nuclear waste (uranium and thorium) that coal power plants exhaust directly into the air every year. Seems like a poor trade. Sure, sounds good. And at night?
The final decommissioning cost is not known - no nuclear power plant has yet been fully "decommissioned". There is also the cost of mishap and security - the cost of Chernobyl, for example, is still adding up (the containment building needs replacement, etc) as well as ongoing. Fantasy, based on various assumptions and omissions. Not a trade I would recommend. But seeing as how none of the proposals for nukes envision actually replacing current coal generation, it's not a trade anyone plans on. And the "unlikely but possible" events are fairly numerous - is the aggregate of them "unlikely"? Is the cost multiplied by the odds - let's say ten million to one, but the one is the loss of most of the current uses of the lower Mississippi River for five hundred years - a good bet compared with the cost of serious coal scrubbing tech, let alone thermal solar? Works fine from storage as well - one of the advantages of the thermal setups is their built in storage capability, and of course more can be added. 100 square miles of high desert in the US Southwest covers the current electrical needs of the US. Ten times that covers everything else. Cheap compared with the military and related costs of containing North Korea's, Russia's, Pakistan's, India's, Iran's, etc etc etc into infinity, ambitions - one of the many side effects of nukes that never seem to be added to the balance sheets.
Something has to replace it eventually if we have any hope of reducing our CO2 output. Nuclear is our best option. Yes. You would have a far, far higher chance of, say, being struck and killed by the space station than being harmed by nuclear power plant waste getting into your water. Yes, it is. The risks associated with coal scrubbing are not zero, either. Let's say you do manage to scrub all the nuclear waste out of the flue gas of coal power plants. Where will you dump it? How will you ensure it does not end up in your drinking water, or in the Mississippi? There will be about 130 million tons of the stuff a year instead of about 2000 tons of nuclear waste a year; how will you handle a 100,000 times the waste for less cost and with less risk? No one has any plans for any kind of storage system that can supply even a fraction of our baseline needs. Great. That works until it's nighttime, or there are a few days of bad weather. Solar, wind etc are great opportunistic power sources. They are not baseline sources; we still need to generate power even when the sun's not out and the wind isn't blowing. The only two sources that can reasonably supply tat power are coal and nuclear. Coal generates far more nuclear waste (and far, far more toxic waste) than nuclear. Coal kills about 30,000 people a year, mainly from particulate emissions; nuclear kills a few, mainly from mining accidents. The question is not "should we avoid nuclear waste by avoiding nuclear power plants?" You can't do that. The question is "how much nuclear waste do you want in the air you breathe and the water you drink?" If the answer is "less" then nuclear is the way to make that happen. So use CANDU reactors or thorium reactors. No risk of proliferation.
Belatedly, I realised that the estimable Fraggle actually made a mistake. I do not get the chance to correct this venerable gentleman often, so I take the opportunity. He said : "Within the next 10,000 years, as the glaciers and polar caps melt and release more water into the biosphere, rainfall will increase dramatically and sea level will rise by half a kilometer--more than one-fourth the mean elevation of the state. This may very well cut new rivers that we can't predict" In fact, if all the ice in Greenland and Antarctica melted, sea level rise would be 80 metres, which would flood less than 5% of the United States. Admittedly, that would include all the coastal cities, unless they built some very high dykes. Billvon suggested dumping waste in a subduction zone. There was a research project some years ago looking at that, but they discovered that any container they could design would 'float' on the rock and not be buried - ever. The suggestion that coal burning plants generate more radioactive material than a nuclear plant is, of course, quite correct. That is not the worst feature of burning coal, though. Coal burning is quite the worst way of generating electricity.
It is not. And in fact none of the current plans for nuclear expansion are designed to replace any coal plants at all. So it's hypothetical anyway. Says who? The assumptions behind such calculations are normally ridiculous. For starters, calculating the odds threatening one person misleads: what are the odds of a million people being hit by the space shuttle? I have already been harmed by the mere threat of such contamination - various inconveniences and expenses, as well as risks, from the nuke built at Prairie Island, Minnesota. The people downstream from Three Mile Island, the salmon fishermen downstream on the Columbia River, and so forth, have incurred more risk and harm than that. That's civilian nukes in practice, in the most responsible and capable countries and ideal circumstances. Best get cracking, then. It's far more easily handled than decommissioning hundreds of nuclear power plants, or trying to tap fusion for power, or the like. There are several working methods already, that could be expanded, and that from peanuts in funding and hobby level efforts in engineering. The childish stuff is getting old. You do know that people have kind of figured this out a little better than that, right? Please. Weapons proliferation is a possible consequence of any nuclear power technology. India's bomb program was leveraged off of CANDU power plants.
Nuclear power to weapons??? In fact, while this is possible, it is extremely difficult. To make a nuclear weapon requires, more than anything else, a supply of fissionable material of sufficient purity. Nuclear power requires fissionable material of much lower purity. That is : fuel for nuclear power cannot be used for nuclear weapons without major purification, and that is very, very difficult. It takes a major government funded research effort to learn to do that. No terrorist organisation would bother. Safety of nuclear power? There are four major forms of generating electricity in the world today. Hydroelectricity, coal burning, nuclear, and natural gas. Others like wind power still produce less than 2% of the world supply. Of those four, nuclear is the second safest. Hydroelectricity has killed thousands. A single dam burst in India in the 1960's killed about 10,000 people. Coal burning is the most hazardous, and globally kills literally hundreds of thousands each year through causing respiratory illness. Only natural gas is safer. Chernobyl is often quoted as the reason for calling nuclear unsafe. But the International Atomic Energy Agency estimates that no more than 2500 people in total have died or will die as a result of Chernobyl, including all causes. This is a damn sight less than either hydroelectricity or coal burning.
practically all of it just think of the hard data that frames more basic questions like "How much would the sea rise if the polar caps melted?" (and the ensuing lack of consensus on an answer) and you can begin to understand the problems with gathering hard data on the problem ...
That's a good example of ignorance harming people. Another example would be how minorities moving into an area "harms" someone because their property values go down. The right answer to that is not to keep minorities out; a better solution is education to try to remove some of the prejudices people have against minorities. No, they really haven't. I've installed a bunch of solar power systems. The off-grid ones use banks of lead acid batteries. They're pretty bad ecologically and a pain in the butt to maintain. But for small systems, that's the best we can do. Just north of me they are planning a pumped storage plant. It's state of the art; again, the best we can do currently. It's sited near a big lake and a mountain range, which is what you need for pumped storage (vertical head, storage area and a water source.) At maximum output it will generate 500 megawatts for 12 hours. That's the best they can do without damaging the lake, which is the largest in Southern California. California demand at 2am at night, during the minimum power time, is 19,000 megawatts. We'd need 38 of these plants to supply baseline usage even at our lowest daily usage. So we'd just need 37 more lakes near mountain ranges - combined with a very draconian conservation program to ensure demand never rises over bare minimums at night. Will projects like the above help? Definitely. Will it replace baseline generation? No. We need to supply that with either fossil fuels or nuclear power. The question is - which is the better choice? Of course. You could make a nuclear weapon out of coal. But without enrichment, it's very, very hard to construct it.
Frankly, LG, I think you do not have a clue, but are trying to throw quibbles at me just to be difficult. Oh, well, I can play your silly game. If all the ice in Greenland and Antarctica melted, sea levels would rise a calculated 80 metres. The average depth of the oceans is 3790 metres. Thus the ocean depth would increase a measley 2%. All this data is available via google.
Right there is my problem. How can we predict how much nuclear waste will be produced in the future? Mankind's consumption of energy makes a quantum jump every time a new source of energy is discovered. Human muscles Animal muscles Fossil fuels Nuclear reactions How big is that last quantum jump going to be once nuclear energy fulfills its promise of being "too cheap to meter"? No one in the 17th century could have imagined the technologies we would develop after the Industrial Revolution, nor the volume of fuel those technologies would burn. Why should we suppose that, from our own unenlightened vantage point, we can predict the energy consumption of civilization 400 years from now? They will be doing things that we can't imagine, that we have no words for, and that use power at a rate we can't confidently estimate. Your calculations are all based on a relatively steady rate of power use. If there's one thing we've learned from history, it's that we can't predict the future accurately. And if there's a second thing, it's that humans squander resources. I'm worried about what sorts of outrageous acts will be performed by desperate governments and other institutions during the collapse. Bombing each other's waste dumps in an attempt to kill their citizens, and in the process making huge areas of land uninhabitable? Digging up the waste to use in some hare-brained military plan borne out of desperation, accomplishing something similar? Yeah, sorry. I read the graph in the Wikipedia article on Sea Level wrong. (Or else it was already wrong and they fixed it.) We're near the high end of the cycle, not the low end. My apologies. They also revised it since the last time I looked it up and the total change is more like 200m instead of 500m. (Which sounds low to me.) Maybe they'll eventually get it right.
Sorry, I have to correct you. Please Register or Log in to view the hidden image! Fissionable materials of any grade aren't adequate for nuclear weapons and can be used for power generation, but aren't optimal. It is fissile materials that hold this distinction (can fission in the presence of thermal neutrons). This is why Uranium 235 is used as fuel instead of the major component of natural Uranium, U-238. 238 is fissionable, while 235 is fissile. The assay of enriched uranium required for sustained nuclear reactions is about .9% (in heavy water reactors, due to higher thermal neutron density), and about 3% in normal PWRs and other "light" water reactors. The assay required for weapons use is only about 20%, although most weapons utilize 85% and higher. It is difficult to compare what a well funded terrorist or paramilitary organization could do with nuclear weapons to the Manhattan Project, or other government projects keyed towards nuclear weapons. First, the Manhattan project was really a first. While Germany also was trying to develop nuclear weapons, no country really knew how to make them. They had to solve a lot of theoretical and engineering problems during the course of the program, using several methods at the same to both in weapon designs and the enrichment of uranium (as well as producing plutonium). Second, like any government program, it was inefficient. Even though the Manhattan project was probably the best example of what a government can do when it stops being so bureaucratic for a bit, it still was unable to do what a private sector (or criminal) run organization could have done with the same resources. Considering all of this, in the modern day, those engineering feats were solved long ago. It is very easy to research how to both enrich uranium as well as build a bomb, as long as you have people who have the scientific and engineering backgrounds who can use that information. 20 or 30 years ago, it would have been too much of a major undertaking to enrich uranium to weapons use or even worse, "weapons grade" (85% or more) assay due to the common, inefficient enrichment methods that were used, such as gas diffusion. The gas centrifuge method has changed all of that, since it requires far less power and is much easier to implement. This is why governments and the IAEA get nervous when they find out about centrifuge parts being shipped to nations like Iran. Such a program could be implemented by a terrorist organization backed by billions of dollars...and that is not an impossibility. Considering the ties many terrorists have to the oil industry and to some nation states, it could happen. The most likely scenario would be 1 or 2 low yield weapons using less than 50% assay of 235. The destructive capability of such weapons is far smaller than the perception of what a normal nuclear weapon can do. But, for the cause of terror, it would be disastrous. "Dirty" bombs are also a concern, which require little or no enrichment, or even a complicated delivery system. With all of that said...I do agree that no terrorist organization would bother with building a nuclear weapon, although they might try a "dirty" bomb, which is far cheaper. As for Chernobyl, it was just one of many disasters in the Soviet nuclear program. The disaster was caused by a combination of poor engineering, and poor process control. The reactor design itself was inherently unstable. There was a far worse nuclear disaster in Soviet Russia that took place over the span of several decades. I did a paper on the Chelyabinsk/ Lake Karachay disaster. If you ever have a chance, read about it. It shows that the Soviet nuclear program's problems were definitely pathological and in every part of the system. Chernobyl was just the final blow.
Fraggle said : "Right there is my problem. How can we predict how much nuclear waste will be produced in the future? Mankind's consumption of energy makes a quantum jump every time a new source of energy is discovered" However, there is also another trend in human technology. One towards greater efficiency and less waste. I suspect that 200 tonnes a year of waste radio-isotopes is about the maximum, even if nuclear power generation increases ten fold. We will simply use more of the energy available, and generate less waste. Also, I doubt that nuclear fission will remain as number 1 too long. Nuclear fusion is potentially far better. And it produces far less waste.
Yes Google is certainly a good tool to use to see how there is no consensus on 80 metres ... the main bone of contention being understanding what effects the accompanying climate change that caused the ice to melt (eg - evaporation and rainfall) would have. :shrug: Your ideas are very linear and not realistic - kind of like estimating that since it takes 3 men 300 minutes to dig a 1 metre hole, 300 men could dig it in 3 minutes ....
LG Lack of consensus in this case is simply an argument of how wide the error bars are. If the sea level rise was 100 or 60 metres instead of 80, it will not change my argument.
